/**
 * Copyright &copy; 2012-2016 <a href="https://github.com/HuangBingGui/jeespring">jeespring</a> All rights reserved.
 */
package com.jeespring.common.servlet;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.math.NumberUtils;

import com.jeespring.common.utils.IdGen;

/**
 * 生成随机验证码
 * 
 * @author 黄炳桂 516821420@qq.com
 * @version 2014-7-27
 */
@SuppressWarnings("serial")
@WebServlet(urlPatterns = "/servlet/validateCodeServlet")
public class ValidateCodeServlet extends HttpServlet {

    public static final String VALIDATE_CODE = "validateCode";

    // private int w = 70;
    // private int h = 26;
    private int w = 80;
    private int h = 40;

    public ValidateCodeServlet() {
        super();
    }

    @Override
    public void destroy() {
        super.destroy();
    }

    public static boolean validate(HttpServletRequest request, String validateCode) {
        String code = (String) request.getSession().getAttribute(VALIDATE_CODE);
        return validateCode.toUpperCase().equals(code);
    }

    @Override
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String validateCode = request.getParameter(VALIDATE_CODE); // AJAX验证，成功返回true
        if (StringUtils.isNotBlank(validateCode)) {
            response.getOutputStream().print(validate(request, validateCode) ? "true" : "false");
        } else {
            this.doPost(request, response);
        }
    }

    @Override
    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        createImage(request, response);
    }

    private void createImage(HttpServletRequest request, HttpServletResponse response) throws IOException {

        response.setHeader("Pragma", "no-cache");
        response.setHeader("Cache-Control", "no-cache");
        response.setDateHeader("Expires", 0);
        response.setContentType("image/jpeg");

        /*
         * 得到参数高，宽，都为数字时，则使用设置高宽，否则使用默认值
         */
        String width = request.getParameter("width");
        String height = request.getParameter("height");
        if (StringUtils.isNumeric(width) && StringUtils.isNumeric(height)) {
            w = NumberUtils.toInt(width);
            h = NumberUtils.toInt(height);
        }

        BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
        Graphics g = image.getGraphics();

        /*
         * 生成背景
         */
        createBackground(g);

        /*
         * 生成字符
         */
        String s = createCharacter(g);
        createLine(g);
        request.getSession().setAttribute(VALIDATE_CODE, s);

        g.dispose();
        OutputStream out = response.getOutputStream();
        ImageIO.write(image, "JPEG", out);
        out.close();

    }

    private Color getRandColor(int fc, int bc) {
        int f = fc;
        int b = bc;
        if (f > 255) {
            f = 255;
        }
        if (b > 255) {
            b = 255;
        }
        return new Color(f + IdGen.nextInt(b - f), f + IdGen.nextInt(b - f), f + IdGen.nextInt(b - f));
    }

    private void createBackground(Graphics g) {
        // 填充背景
        // g.setColor(getRandColor(220,250));
        g.setColor(new Color(255, 255, 255));
        g.fillRect(0, 0, w, h);
        // 加入干扰线条
        // 干扰线条先注释
        for (int i = 0; i < 20; i++) {
            /*
             * g.setColor(getRandColor(40,150)); Random random = new Random(); int x =
             * random.nextInt(w); int y = random.nextInt(h); int x1 = random.nextInt(w); int
             * y1 = random.nextInt(h); g.drawLine(x, y, x1, y1);
             */
        }
    }

    private void createLine(Graphics g) {
        // 加入干扰线条
        // 干扰线条先注释
        int times = IdGen.nextInt(25);
        for (int i = 0; i < times; i++) {
            // g.setColor(getRandColor(40,150));
            g.setColor(new Color(255, 255, 255));
            int x = IdGen.nextInt(w);
            int y = IdGen.nextInt(h);
            int x1 = IdGen.nextInt(w);
            int y1 = IdGen.nextInt(h);
            g.drawLine(x, y, x1, y1);
        }
    }

    private String createCharacter(Graphics g) {
        /*
         * char[] codeSeq = {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'M', 'N',
         * 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '2', '3', '4', '5',
         * '6', '7', '8', '9' };
         */
        char[] codeSeq = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };
        // String[] fontTypes = {"Arial","Arial Black","AvantGarde Bk BT","Calibri"};
        // String[] fontTypes = { "Ravie", "Antique Olive Compact", "Fixedsys", "Wide
        // Latin", "Gill Sans Ultra Bold" };
        StringBuilder s = new StringBuilder();
        for (int i = 0; i < 4; i++) {
            String r = String.valueOf(codeSeq[IdGen.nextInt(codeSeq.length)]);// random.nextInt(10));
            // g.setColor(new Color(50 + random.nextInt(100), 50 + random.nextInt(100), 50 +
            // random.nextInt(100)));
            g.setColor(new Color(70, 70, 70));
            // g.setFont(new
            // Font(fontTypes[random.nextInt(fontTypes.length)],Font.BOLD,26));
            g.setFont(new Font("Arial", Font.ITALIC, 18));
            // g.drawString(r, 15 * i + 5, 19 + random.nextInt(8));
            g.drawString(r, 20 * i + 4, 26);
            s.append(r);
        }
        return s.toString();
    }

}
